This invention relates to an apparatus for separating particulate material from hot gas, the apparatus being commonly known as a cyclone separator. The invention also pertains to a method of constructing such apparatus. With increasing demand to eliminate air pollution accompanied by stringent antipollution laws, and with the need for maximum conservation of energy, there has been a continuing effort to seek out means of improving such cyclone separators.
Perhaps the simplest form of cyclone separator comprises a cylindrical barrel having an inlet orifice extending axially along one end of its periphery and a short gas outlet or discharge tube extending axially along the length of said inlet orifice and outwardly beyond a flat disc member closing the end of the separator between the barrel and said outlet tube. The opposite end of the barrel is open for discharge of the separated particulates.
Cyclone separators of this simple type have been researched and analyzed over the years almost to what one could characterize as the point of exhaustion. Such research invariably has had two primary goals: to increase the efficiency and to provide ways of separating smaller and smaller particulates. In particular, in the removal of residual catalyst in the effluent flue gases from the fluid catalyst cracking process as used in the petroleum industry there has been a continuing struggle to retrieve more and more catalytic particulates as far down as the 5 micron diameter range.
In the light of this background it is extremely surprising that unsuspected problems have now been solved resulting, as demonstrated by actual tests, in 100% recovery of 5.5 micron particulates and as much as 50% of 3 micron particulates. In fact, it is now feasible to make significant recovery of particulates with diameters as low as 1.5 microns.